<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>盒子模型 - 非常重要</title>
    <style>
        .c1{
            border: 10px solid red;
            width: 300px;
            height: 300px;

            /* 内填充 */
            /* padding-left: 30px;
            padding-top: 50px; */
            /* 影响到了box的宽度和高度
            宽度 - 10 + 10 + 30 + 300
            */

            padding: 30px;

            /* css3.x - 盒子的宽度 = width*/
            box-sizing: border-box;

            /* margin-bottom: 10px; */

            float: left;
        }

        .c2{
            /* margin - 外间距 */
            border: 10px solid yellow;

            margin-left: 10px;

            float: left;
        }


    </style>
</head>
<body>
    <div class="c1">
        山科大dfdfd <br>
        dsfd
    </div>

    <div class="c2 c1">
        山科大dfdfd <br>
        dsfd
    </div>
</body>
</html>